The present invention relates to a hydrazone compound and a photosensitive material using such a compound.
As an electrophotosensitive material in an image forming apparatus such as an electrophotographic copying apparatus, a printer, a facsimile or the like, there is recently widely used an organic photosensitive material which is excellent in machinability and advantageous in production cost and which offers a great degree of freedom for design of performance.
For forming a copied image with the use of an electrophotosensitive material, the Carlson process is widely used. The Carlson process comprises the steps of uniformly charging a photosensitive material with electricity by corona discharge, exposing the charged photosensitive material to a document image, thereby to form an electrostatic latent image corresponding to the document image, developing the electrostatic latent image by a toner-containing developer, thereby to form a toner image, transferring the toner image to a medium such as paper, fixing the toner image transferred to the medium, and cleaning the photosensitive material to remove toner remaining thereon after the toner image has been transferred. To form an image of high quality in the Carlson process, it is required that the electrophotosensitive material is excellent in charging and photosensitive characteristics and presents a low residual potential after exposed to light.
As examples of the electrophotosensitive material, there are conventionally known inorganic photoconductive materials such as selenium, cadmium sulfide and the like. However, such materials are disadvantageous in view of toxicity and high production cost.
Accordingly, there are proposed so-called organic electrophotosensitive materials using organic materials instead of the inorganic materials. Each of the organic electrophotosensitive materials has a photosensitive layer comprising an electric charge generating material adapted to generate an electric charge upon exposure to light, and an electric charge transferring material for transferring an electric charge generated.
To satisfy a variety of requirements necessary for the organic electrophotosensitive material, it is required to properly select the electric charge generating material and the electric charge transferring material. As examples of the electric charge transferring material, a variety of organic compounds are proposed and put on the market. For example, there are known hydrazone compounds disclosed by Japanese Patent Unexamined Applications 131954/1983, 298364/1989 and 210451/1990.
However, these conventional electric charge transferring materials are poor in sensitivity and repeating characteristics.